In a plasma processing chamber, such as a plasma etch or plasma deposition chamber, the temperature of a chamber component is often an important parameter to control during a process. For example, a temperature of a substrate holder, commonly called a chuck or pedestal, may be controlled to heat/cool a workpiece to various controlled temperatures during the process recipe (e.g., to control an etch rate). Similarly, a temperature of a showerhead/upper electrode, chamber liner, baffle, process kit, or other component may also be controlled during the process recipe to influence the processing. Conventionally, a heat sink and/or heat source is coupled to the processing chamber to maintain the temperature of a chamber component at a desired temperature. Often, at least one heat transfer fluid loop thermally coupled to the chamber component is utilized to provide heating and/or cooling power.
Long line lengths in a heat transfer fluid loop, and the large heat transfer fluid volumes associated with such long line lengths are detrimental to temperature control response times. Point-of-use systems are one means to reduce fluid loop lengths/volumes. However, physical space constraints disadvantageously limit the power loads of such point-of-use systems.
With plasma processing trends continuing to increase RF power levels and also increase workpiece diameters (with 300 mm now typical and 450 mm systems now under development), a temperature control system capable of both a fast response time and high power loads is advantageous in the plasma processing field.